We have the following inside our sharepoint server 2013 enterprise on-premises:-
An enterprise Wiki Site collection, which have enterprise wiki sub-sites representing our customers.
Now, we want our customers' project managers to be able to access the sub-site representing their company to be able to read the wiki pages and edit them.
Now, of course, those project managers are not defined inside our AD, and they cannot access our network.
So, how can I allow external users to access our SharePoint On-Premises sites? Of course, I am not asking this question from a network perspectives, as our network team mentioned that using VPN external user can be permitted to access specific urls within our SharePoint intranet, but I am asking if SharePoint On-Premises 2013 provides some facilities to allow non-AD users to access the sites?
Second question: Now, when any wiki page is edited inside our sites, an email will be sent to a username named "Assigned to", so the user can approve/reject the changes. This email is being sent inside a SharePoint Designer's workflow 2010. Now, if we manage to allow external users to access our sites, then will the 2010 workflow support sending emails to external users?